The present invention relates to an electrical connector and more specifically to an electrical connector used to connect printed circuit boards.
High speed electronic digital computers of the type produced by Silicon Graphics, Inc., the assignee hereof, typically require multitudes of electrical connections between various printed circuit cards within a system. Presently, one printed circuit board or mother board is provided with a plurality of connectors along one surface. Other printed circuit boards, called daughter boards, include edge connectors and are attached or plugged into the plurality of connectors on the mother board. Typically, only one surface of the mother board is provided with connectors and one edge of a daughter board is provided with an edge connector. This prevents problems with stack up tolerance. Currently, a daughter board is not provided with edge connectors on two edges because stack up tolerances make it nearly impossible to connect a daughter board to a mother board and another board. Typically, the motherboard is in a fixed position when one or more daughter boards are plugged into the slots of the motherboard. Adding another motherboard to the daughterboards is nearly impossible to accomplish because of differences due to tolerances between two connectors on each edge of the daughterboard and because of differences due to tolerances between the connectors on the second board. In summary, one motherboard is connected to a number of daughterboards. The daughterboards are connected only to one motherboard. As a result, there is a lack of flexibility in making connections between motherboards and daughterboards. The arrangements for connecting daughterboards to motherboards are limited. There are no interconnection between daughterboards. Furthermore, each daughterboard is connected to only one motherboard. In other words, the number of interconnections between and first board and a second board are limited to one interconnection.
The lack of flexibility in connecting motherboards and daughterboards also causes other sets of problems. Some computer systems are rack mounted. Generally, the various components of the system are placed in vertical racks. The lack of flexibility in connecting motherboards and daughterboards causes problems in rack mounted systems. The problems include accessibility to the motherboard and the daughterboard, and space which must be wasted in order to cool a motherboard and daughterboard xe2x80x9cbrickxe2x80x9d. One common way of mounting motherboards and daughterboards in rack-mounted systems is to have a motherboard which extends horizontally across the back of a rack-mount unit. This motherboard is referred to as a backplane. The backplane has a number of connecters mounted on a surface of the backplane. Daughterboards are connected to the connectors to the connectors on the backplane. The daughterboards are passed through the front of the rack mount unit and then edge connectors are engaged with the slots on the backplane. This system of daughterboards connecting into motherboards allows easy access to the daughterboards. The motherboard or backplane can also be accessed after removing some or all of the daughterboards. One of the problems is that daughterboards only have one connection to another board. In other words, the daughterboards do not interconnect to one another unless through the motherboard.
Motherboards and daughterboards include electrical components that must be cooled. The components on these boards can be air cooled. The problem is that the arrangement of a motherboard serving as a backplane with daughterboards plugging into connectors on the motherboard is somewhat difficult to cool. The motherboard blocks airflow through the brick. The airflow necessary to cool the xe2x80x9cbrickxe2x80x9d must flow around the top and bottom of the motherboard and then past the daughterboards connected into the motherboard. Of course, the airflow could be reversed and also cool the xe2x80x9cbrickxe2x80x9d. The problem is that additional space must be provided to accommodate the airflow. Rack mount systems have different sized racks for different items. The size of the rack is generally fixed in terms of width and depth so the only dimension that varies with individual rack mount portions is the height of the rack mount portion. The height is generally spoken of in terms of Us. One U equals 1.75 inches. The height of the motherboard serving as a backplane is 6 U the height of the rack mount unit is 10 U. In order to cool the arrangement of daughterboards plugged into a backplane motherboard, 4 U must be allotted to provide for sufficient air flow to cool the xe2x80x9cbrickxe2x80x9d. Other arrangements could be designed if the design was not limited to a backplane with a single surface carrying a set of connectors into which the daughterboards were connected. Other arrangements would not require space including 4 U needed for sufficient airflow.
A motherboard with multiple slots into which daughterboards connect requires that a relatively substantial force be applied to the daughterboard in order to force the daughterboard into the connector on the motherboard. There is also a lack of any alignment features which can be used to guide the daughterboard into the slot of the motherboard. People servicing computers have been known to apply a force to the daughterboard while it is not properly aligned. This would be less likely to occur if the connector included alignment guides. A problem with current connectors is that there is a lack of alignment, and a lack of a balance of forces. These add up to a less reliable system.
Therefore, there is a need for a connector that is flexible and which can accommodate differences in tolerance between various boards. There is also a need for a connector which can carry multiple signals. Furthermore, there is a need for a connector that can carry signals between motherboards and daughterboards, and also between daughterboards without having to travel through a motherboard. In other words, there is a need for a connector that allows for connection between any two boards. For example, a connector that allows a daughterboard to connect to another daughterboard in a xe2x80x9cbrickxe2x80x9d. There is a further need for a device that is relatively inexpensive and which is reliable.
A connector system for places a first electrical component in electrical communication with a second electrical component. The connector system includes a first end attached to the first electrical component. The first end has a first portion affixed to one of the first electrical component and the second electrical component. The affixed portion includes a first capture feature. A second portion has a second capture feature which mates with the first capture feature. A third portion is attached to the second portion. One of the first portion and the second portion has an opening therein. The opening has a set of guide ways. The second and third portion are attached by a cam. The cam allows the third portion to move with respect to the second portion. The third portion includes a portion which engages the opening having a set of guide ways. A second end is attached to the second electrical component. A flexible circuit electrically connects the first end and the second end of the connector system. The set of guide ways includes at least two beveled edges of the opening. In some embodiments, the connector system also includes a first set of electrical contacts positioned within the opening, and a second set of electrical contacts positioned on the portion of the connector which engages the opening. Electrical contact is achieved between the contacts when the third portion of the connector engages the first portion of the connector. In some embodiments, the cam is a wedge, or includes a lobe and is rotatable. The flexible circuit is of a length to form a curve when the first end and the second end are connected between the first electrical component and the second electrical component. The first capture feature of the first affixed portion slides with respect to the second capture feature of the second portion. In some embodiments, at least one of the first capture feature and second capture feature is beveled. In other embodiments, the first capture feature and second capture feature include a detent and detent engaging portion. The detent engaging portion engages the detent when the first portion is substantially correctly positioned in a first plane with respect to the third portion. In some embodiments, one of the first capture feature and the second capture feature of the second portion includes a lip and the other capture feature includes a dovetail which engages the lip.
The connector system can also be used as part of a system assembly for a computer. In the system assembly, the connector system is used to connect a motherboard situated on a printed circuit board, and a daughterboard situated on a printed circuit board. In the system assembly the daughterboard is positioned parallel to the motherboard. The connector system allows for multiple connections to be made between a motherboard and a daughterboard in the system assembly. The connector system also allows for multiple connections to be made between a first daughterboard and a second daughterboard in the system assembly.
Also disclosed is a module for a rack mount system including a frame, an air handling device for moving air along a substantially straight air flow path through the frame from a first end of the frame to a second end of the frame, and a plurality of printed circuit boards. The printed circuit boards are removably mounted within the frame. The printed circuit boards have a first edge near the first end of the frame and a second edge near the second end of the frame. The first edge and the second edge of the circuit boards are within the substantially straight air flow path. The plurality of printed circuit boards are substantially parallel to one another. In the rack mount system at least one of the plurality of printed circuit boards includes a system bus thereon. In some embodiments, at least two of the plurality of printed circuit boards include a first electrical contact near one end of the printed circuit board and a second electrical contact near the other end of the printed circuit board. One electrical connector connects between the two electrical contacts near one end of each of the two boards. Another electrical connector connects between two electrical contacts near the other end of each of the two printed circuit boards. In some embodiments, there are at least two electrical connections between at least two of the printed circuit boards.
The actuatable connector has many advantages. Several of the advantages arise from the flexibility the connector affords when configuring motherboards and daughterboards in a computer system. The actuatable connector allows daughterboards to be attached to motherboards while the daughterboard is substantially parallel to the motherboard. This is advantageous since all the printed circuit boards in a system where a number of daughterboards must be connected to a motherboard can be configured to be substantially parallel to one another. This allows for a simple air flow configuration for a rack application. The cooling air would flow past all the boards which are substantially parallel with one another. As a result, there is no need to devote rack space to plenums or xe2x80x9cdead spacexe2x80x9d to allow an air flow path past the printed circuit cards (the motherboard and the daughterboards). This allows for maximum utilization of rack space. In addition, the size of the printed circuit boards is minimized for each application. Since the printed circuit boards can be parallel to one another, the edges of both the daughterboards and the motherboards can be positioned at the two ends of a xe2x80x9cbrickxe2x80x9d or rack mount system. This allows for connection along both edges of a board which is comparable to having two side planes. Advantageously, the motherboards and daughterboards can be connected together without deflection on the board. The acuatable connector has a flex cable which can bend. The flex cable allows for a very large mechanical tolerance so that boards could be connected together in a number of configurations without producing physical strains on other boards or the connectors themselves. In other words, the actuatable connector constrains the forces for mating the connector to the connector system, thereby eliminating deflection problems due to other boards or other elements. In addition, since the boards are placed in parallel with one another, each board can be easily translated in and out of a volume. In the past, more elaborate translation systems were used since one card would have to plug into another card positioned as a backplane.